per = through + lucere = to shine; translucent; e.g., zona pellucida of ovarian follicle; septum p. of brain.

adjective, Latin per = through, and lucere - to shine; hence, translucent.

L. pellucidus, allowing the passage of light, transparent. Septum pellucidum is a thin membrane extending between the corpus callosurn and fornix. It separates the frontal horns of the lateral ventricle. First described by Galen (130-201 A.D.)